President Barack Obama on Saturday strongly condemned "the brutal murder" of a Japanese hostage held by Islamic State militants, and he vowed Washington and its allies would "bring the perpetrators ... to justice."
Obama's statement came hours after a video showed one of the Japanese hostages, journalist Kenji Goto, holding up photos appearing to show beheaded co-captive Haruna Yukawa.
The Islamic State group, which now holds a third of both Syria and Iraq, had threatened Tuesday to behead the hostages within 72 hours unless it received a $200 million ransom.
In the video, a man's voice purporting to be that of journalist Goto is heard in English, with Arabic subtitles. The man directly addresses Japanese Prime Minister Shinzo Abe, accusing him of responsibility for Yukawa's death.
He said the militants no longer wanted money and were instead demanding the release of Sajida al-Rishawi, a female suicide bomber candidate imprisoned in Jordan.
In Tokyo, the Japanese prime minister condemned the release of the grisly video and vowed that his government would not give in to terrorism.
The White House statement pledged "decisive action to degrade and ultimately defeat" Islamic State extremists.
U.S. Secretary of Defense Chuck Hagel released a statement saying Islamic State's "inhumanity stands in sharp contrast to the generous humanitarian aid Japan has provided to the Iraqi and Syrian people in recent months, and their continued barbarism only serves to strengthen our global coalition's shared resolve to degrade and ultimately destroy" the terrorist group.